Some of the existing solutions of the prior art are described in the following patents: EP-0.923.386 B1 (FIG. 1a), EP-1.082.970A1 (FIG. 1b), EP-1.698.355A1 (FIG. 1c).
Containers with membrane having two or more compartments for containing volatile substances of different nature are known in the state of the art. This is the case of the patents EP-1.082.970, WO-06084921 and EP-1.698.355.
Evaporation of two different volatile substances thorough membranes of different containers is also disclosed in the Japanese patent JP-02252462, although for a different purpose of the device object of the present invention.
Other documents generally related to the use of evaporation of volatile substances thorough semi-permeable membranes are: EP-0.923.386, U.S. Pat. No. 5,575,992, WO-05014061 and WO-97/42982.
All above inventions do not provide any means to release a fragrance A and, at the same time, appreciably reducing the evaporation of a fragrance B, and viceversa, or mixing the two fragrances, at user's will. The existing solutions to reduce evaporation of active substances through a membrane only consist in closing the housing around the cartridge (container of the volatile substance) but not the cartridge itself, so that evaporation induced by temperature can occur also, leading to:                exit of the housing if the closure is not completely impermeable or        condensation in the container if it is impermeable.        
Existing devices do not provide effective means to appreciably reduce the evaporation of a substance. The present invention allows to appreciably reduce the evaporation of a substance whilst the evaporation of another substance is increased.